The phenomenon of horizontal finger nail lines may be due to malnutrition, parasitic infection, nail fungus disease and other factors. 1. Malnutrition: If the patient often picks and favors food, he/she may lack nutrients in the body, which will lead to the appearance of horizontal nail lines and dry symptoms. 2. Parasite infection: when there are parasites in the patient’s body, it may cause symptoms such as increased food intake, body thinning, nail streaking and other related symptoms, which can be clearly diagnosed through examination. 3. Ringworm disease: also commonly known as “gray nails”, usually caused by ringworm infection of the nails, which can cause nail plate wrinkles, turbidity, thickening, brittleness, discoloration, and even fall off. There may be other reasons for the horizontal striping of finger nails, so you need to cooperate with your doctor to complete the examination and determine the cause before handling and treatment.